The photocatalytic particles induce several effects such as antifouling effect, defogging, bactericidal effect, odor eliminating and air purification by high reducing power of photoexcited electron and high oxidation power of electron hole. Therefore, the photocatalytic particles are developed in various fields such as articles for daily use, building products and civil engineering. Visible light reaction type photocatalytic particles reacting to visible light are developed recently and can be used in the room in which the amount of ultraviolet ray is low.
In order to use the beneficial effects of the photocatalytic particles in various fields such as articles for daily use, building products and civil engineering, it is necessary to bond the photocatalytic particles tenaciously on the various base substrate in such a manner that photocatalytic function is maintained and does not cause a negative effect on the base substrate.
When the base substrate on which the photocatalytic particles are bonded is made from resin, the resin base substrate deteriorates due to high oxidation power of the photocatalytic particles. Therefore the following problems are caused. That is, the photocatalytic function is decreased by eliminating the photocatalytic particles from the base substrate and the resin base substrate does not fulfill one's original function.
When the photocatalytic particles are bonded on the surface of the fiber, film and molding body made from resin, the bonding method of the photocatalytic particles which represses deterioration of resin is an important technique in terms of usefulness.
Conventionally, as the method for bonding the photocatalytic particles on the resin base substrate, there are the methods with organic binder such as fluorine resin or silicone resin which is hardly to deteriorate against high oxidation power of photocatalytic particles (See Patent Documents 1 and 2) The methods for preventing the photocatalytic particles from contacting with the resin base substrate were disclosed. For examples, the methods in which inorganic membrane made from silicon-oxide (SiOx) or aluminum oxide is formed on the surface of the resin base substrate through sputtering method was disclosed (See Patent Documents 3 to 5).
When the fluorine resin consisted of tetrafluoroethylene which has the highest oxidation resistance is used as binder, it is difficult to bond the photocatalytic particles on the surface of the resin base substrate. Therefore, in order to improve adhesiveness of the photocatalytic particles, thermosetting resin is added thereto. When resin containing carbon hydride is added together with fluorine resin, the resin containing carbon hydride is dissolved by high oxidation power of the photocatalytic particles. Therefore, chromatism and afoul smell are caused. When silicone resin is used as binder, it is difficult to secure adhesiveness of the photocatalytic particles and the resin base substrate and to form uniform fixed layer of the photocatalytic particles depending on the component of the silicone resin.
On the other hand, in order to prevent the photocatalytic particles from contacting with the resin base substrate, the method in which dense inorganic membrane made from oxides of silicone or aluminum oxide is formed on the surface of the resin base substrate through sputtering method is disclosed. However, it is difficult to form the inorganic membrane having excellent adhesiveness depending on the difference of thermal expansion coefficient between the resin base substrate and the inorganic membrane and depending on the component of the resin. Furthermore, the resin base substrate change shape due to heat produced in sputtering method and productivity is decreased. Thus there are several problems as mentioned above, which need to be solved.
(Patent Document 1:
Japanese Patent Application Laid-Open No.H10 (1998)-216210)
(Patent Document 2:
Japanese Patent Application-Laid-Open No.H10 (1998)-001879)
(Patent Document 3:
Japanese Patent Application Laid-Open No.H08 (1996)-215295)
(Patent Document 4:
Japanese Patent Application Laid-Open No.H10 (1998)-17614)
(Patent Document 5:
Japanese Patent Application Laid-Open No. 2002-248355)